The article considers the issues of improving the technology of preparing concrete mixtures for road surfaces at existing concrete mixing units without additional costs for their technical re-equipment. The essence of improving the preparation of concrete mixtures lies in the complex use of carbonate microfiller and superplasticizer additives in combination with the developed innovative method of preparing concrete mixture. The article shows that when using a polycarboxylate superplasticizing additive and a microfiller based on porous shell limestone in combination with the proposed method of preparing concrete mixture, it is possible to obtain road concrete with the required strength properties with a cement consumption reduced by 50 kg/m³.
Keywords: road concrete, superplasticizer, mineral micro filler, method of preparation of concrete mix
Disposal of drilling waste in construction The methods of disposal of drilling waste are considered and the mechanisms of their biological purification by microorganisms are described. A technology for the disposal of biologically purified drilling mud is proposed by manufacturing concrete structures of marine artificial reefs, barrier breakwaters and other products on an offshore platform. Compositions of fine-grained fiber-concrete mixtures have been developed, including Portland cement, biologically purified well drilling waste, basalt fiber fibers and superplasticizer "SP-3". The sufficiently high parameters of the strength characteristics and frost resistance of the obtained fiber concrete compositions have shown the possibility of their use in harsh climatic conditions. materials
Keywords: drilling waste, biodegradation, fine-grained fiber concrete, dispersed reinforcement, mechanical properties, offshore platform
The article examines the features of dismantled paving slabs as raw materials for the production of recycled aggregate for concrete. The effect of crushed fine fractions of secondary crushed stone screenings on the properties of fine-grained self-compacting concrete was investigated. It was experimentally shown that the use of this material as a mineral additive leads to an increase in the water demand of the self-compacting fine-grained mixture and a significant decrease in strength.
Keywords: demolition waste, vibro-pressed paving slabs, recycling, screening of secondary crushed stone, mineral additive, self-compacting fine-grained concrete, consistency of concrete mix, strength, shrinkage
The importance of recycling construction waste for the development of closed-loop economy technologies in the construction industry is considered. The effect of replacing high-quality granite and limestone crushed stone with secondary aggregate obtained by crushing concrete scrap on the strength properties of geopolymer concrete was investigated. It was established that such a replacement does not lead to a decrease in the strength of such concrete, and the impact resistance increases significantly.
Keywords: demolition waste, concrete scrap, recycling, geopolymer concrete, blast furnace granular slag, crushed stone crushing screening, closed-loop economy technologies, secondary aggregate, strength, impact resistance
The use of the contact angle as a criterion for the degree of hydrophobization of a solid surface and gypsum particles in suspensions containing surfactants showed that an increase in the concentrations of ethyl silicone oil and soap naphtha in the initial gypsum suspensions led to an increase in the contact angle of wetting of solid particles to 82.5° and 77.5°, respectively. However, on the surfaces of the formed solid samples containing ethyl silicone oil, a drop of water spreading and its rapid absorption were observed. Solid samples containing soap naphtha in an amount of 3% had a hydrophobic surface characterized by a contact angle of 82.2°. Probably, the hydrophilic and hydrophobic properties of the solid surface of the material are determined by its bulk structure at the stage of formation, including under wave action. In this case, the porous-capillary structure of the formed samples containing gypsum and surfactants affects the determination of the wetting criterion.
Keywords: contact angle, hydrophobization, gypsum, soap naphtha, ethyl silicone oil, ultrasonic treatment
In the production of bitumen-mineral mixtures, it is proposed to use artificial granite as a filler - waste from the production of porcelain stoneware (OPK). To assess the durability of road and pavement network coatings, a method for determining the aging coefficient of bitumen-mineral mixtures was developed. It was concluded that in the presence of sand from the screenings of crushed porcelain stoneware, the bitumen binder of fine-grained BMS is less susceptible to aging processes.
Keywords: artificial granite, aging of bitumen binder, aging coefficient, sand from crushing screenings
The article describes the process of sedimentation in water treatment, as well as the formation of tap sludge. A new method of water supply sludge treatment with coagulant regeneration at high turbidity of initial water is proposed. On the basis of the conducted research it is revealed that the greater the coagulant consumption obtained by the sulfatization method, the better the degree of coagulation. The basic technological scheme of water sludge processing by sulfatization method is developed. It is suggested that the obtained coagulant from water supply sludge can be used for repeated preliminary sedimentation. Taking into account the urgency of the problem of providing the population with clean drinking water, it is recommended to conduct pilot testing of the obtained coagulant from tap sludge by the sulfatization method.
Keywords: water treatment, tap sludge, daily regulation basin, sedimentation, turbidity, sulfatization method
The paper presents the results of research into the efficiency of fine-grained concrete made using substandard materials and complex modifying admixture. The aim of the work is to evaluate the effect of multicomponent admixture on strength characteristics and efficiency of concrete. For this purpose the fractional factor experiment with variation of seven factors was applied, which were: microsilica, superplasticizers and other additives influencing both the properties of fine-grained concrete mixture and the properties of fine-grained concrete. The main criteria for assessing the influence of complex modifying admixtures were taken as the coefficient of structural quality and specific cement consumption per unit strength. The conducted research allowed to establish that the optimal composition of the additive increases the CQC by 29.9% and reduces the specific cement consumption by 24.6% in comparison with the control samples. It is shown that a balanced combination of additives improves the performance properties of concrete, contributing to resource saving and reducing the environmental load.
Keywords: fine-grained concrete, substandard materials, complex modifying admixture, structural quality coefficient, specific cement consumption, mathematical planning of the experiment, resource saving, compressive strength
The effect of nanosized boehmite microadditives on the surface properties of carboxymethyl cellulose polymer suspensions with aluminum microparticles was studied. It was found that with an increase in the boehmite content from 0.10 g to 0.20 g in suspensions, the surface tension of liquid systems increases by 8 mN/m. The contact angle of the liquid composition wetting the fluoroplastic surface also increases: from 62 ° to 85 °. It is shown that on a low-energy fluoroplastic surface, boehmite nanoparticles act as a pore-forming agent, leading to the generation of ordered cells on the surface of films formed from suspensions. The morphology of the initial powders and the formed films with cells was studied using optical and electron microscopy. It was established that ordered cells of similar size with dimensions of ratio 500 to 1,000 microns in size are formed with a boehmite content in the base composition of 0.15 g.
Keywords: carboxymethyl cellulose, aluminum powder, nanosized boehmite, suspension, surface tension, wetting angle, pore
The article is a continuation of the research on increasing the durability of heavy concrete and extending the life cycle of structures. The objective of the study is to determine the effect of the action of microsilicon and trepel additives introduced into the concrete mixture on increasing the strength characteristics of concrete. A control composition of a given concrete class in terms of strength B60, class F400 frost resistance and W20 water resistance, with the addition of superplasticizer ST 5.0, was selected. A comparative analysis of various concrete compositions was carried out in order to increase their strength characteristics and density. As a result of experiments, it was found that the introduction of 5% silica or trepel, as well as their combinations, helps to achieve a given strength class of B60 and increase the density of concrete. The use of superplasticizer ST 5.0 ensures the necessary mobility of the mixture without increasing the water-cement ratio, which improves the durability and performance of the materials. The results obtained allow us to recommend additives for the production of high-strength concrete with improved technical performance.
Keywords: silica, concrete strength, trepel, concrete mix, superplasticizer, water-cement ratio, heavy concrete, active mineral additives, concrete, MCU-85
The reuse of ash and slag waste from coal combustion is of great economic and environmental importance. The most material-intensive area of their reuse is the stabilization of ash and slag mixtures with Portland cement for the construction of layers of highways. A technical understanding of the processes of structure formation in stabilized ash and slag mixtures makes it possible to regulate the final properties and quality of the layers of road clothing and the roadbed. Strengthening of ash and slag mixtures with Portland cement makes it possible to increase the physical and mechanical properties of ash and slag mixtures: strength, frost resistance, density, etc.
Keywords: ash and slag mixtures, stabilized ash and slag mixtures, structure formation of stabilized ash and slag mixtures, sportland cement, microstructure of the ash and slag mixture
We conducted experimental studies to determine the thermal conductivity of polyurethane foams with different structural parameters, such as cell type and size. The purpose of the study was to investigate the contribution of radiant heat exchange to the thermal conductivity of polyurethane foams. The studies were conducted using the ITP-MG4 thermal conductivity meter in two distinct versions. In the first instance, the thermal conductivity of polyurethane foam was measured without the inclusion of a foil layer, whereas in the second instance. The results of the studies demonstrated that, depending on the morphology of the foam, the contribution of radiant heat exchange to thermal conductivity ranges from 5.88% to 15.87%.
Keywords: cellular materials, thermal insulation, polyurethane foam, thermal conductivity, radiation, morphology
The work investigated the effect of the complex application of the nanomodifying additive "Taunit-M", superplasticizer SP-3 and steel fiber "Mixarm" with a diameter of 1 mm and a length of up to 54 mm. The dependence of the amount of introduced steel fiber on the strength characteristics of concrete was established. Data on the stability of the suspension of mixing water with a nanomodifier are given. An improvement in the intensity of concrete strength gain in the early stages of hardening from the introduced complex nanomodifying additive was determined.
Keywords: concrete, carbon nanotubes, ultrasonic dispersion, steel fiber, suspension stability, superplasticizer
The presented article reveals the issue of using waste from the automotive industry of rubber products as one of the possible ways to improve the quality of asphalt pavement and, accordingly, reduce the number of repair activities and material costs for their implementation and increase the service life of the roadway. The tests carried out show that the asphalt-concrete mixture using a modifier based on active rubber powder demonstrates the best mechanical and operational characteristics. The strength and elasticity of asphalt concrete increases, as well as the abrasion resistance decreases, which leads to a longer use time of this web. Such changes in the characteristics of the roadway have a positive effect on the economic side of the issue. Improving the quality of the finished product increases the time intervals between repair actions, which reduces material and resource costs. The adhesion of the road to the rubber of cars is improved.
Keywords: asphalt concrete, asphalt mix, automobile waste, rubber crumb, modifier, active rubber powder
The article is devoted to innovative approaches to the use of environmentally safe polymer binders in the production of thermal insulation materials (TIM) based on vegetable raw materials. The relevance of the work is due to the need to replace traditional synthetic polymers such as polyurethane foam, polystyrene foam, and mineral wool, which in the process of operation emit toxic substances with cumulative properties. Research shows that the use of biopolymers and renewable resources, such as castor oil-based polyurethane resins and casein adhesives, can significantly reduce environmental burdens and improve material safety. Special attention is given to thermoplastic and thermoset matrices, their properties, and applications in composite materials. Thermoplastics such as polyethylene and polypropylene have high impact resistance and recyclability but are limited in application due to the difficulty of processing and high melting point. Thermoset matrices, despite their high strength and resistance to chemical attack, are molded only once, making them difficult to recycle. This article discusses the advantages and disadvantages of different polymer binders and their prospects in the context of environmental sustainability and the efficiency of thermal insulation materials. The research is aimed at improving the physical and mechanical properties of composites and optimizing production processes to create affordable and environmentally friendly thermal insulation materials.
Keywords: innovative approaches, environmentally safe polymers, thermal insulation materials (TIM), plant raw materials, biopolymers, renewable resources, thermoplastics, thermosetting matrices, environmental sustainability, physical and mechanical properties
The article presents the results of studies of the strength properties of heat-protective fiber-gypsum-cement-vermiculite-concrete (FGCPVC) composites with volcanic ash with a maximum grain size of 0.16 mm, polydisperse reinforced with polypropylene RS produced by Russeal and basalt fibers of the RNB-9-1200-4s grade produced by PAO Ivosteklo. Expanded vermiculite of the 0.16–5 mm fraction from the St. Petersburg Mica Factory was used. It was found that the efficiency of the SDO additive at a dosage of up to 0.2% is from 2.3 to 3.1% of entrained air per 0.1% SDO, further increase in the dosage is impractical. Polypropylene fibers do not have a significant effect on the strength properties of FGCPVC composites. Reinforcement of FGCPBB composites with basalt fibers increases the compressive strength by up to 16%, bending strength by up to 73%, the Rf/R ratio with equal compressive strength increases to 51%. Polydisperse reinforcement of FGCPBB composites with basalt and polypropylene fibers increases the compressive strength by up to 40%, bending strength by more than two (2.26) times, the Rf/R ratio with equal compressive strength increases to 65%.
Keywords: gypsum, portland cement, ash, expanded vermiculite, polypropylene and basalt fibers, composites, compressive and flexural strength
The article discusses the use of liquid chlorides of natural genesis to combat winter slipperiness. The aggressive effect of liquid chlorides on snow removal equipment, road structural elements and the environment as a whole is also studied. Methods for assessing the effect of liquid chlorides on metal and cement concrete are developed. The article presents conclusions and recommendations on the use of liquid natural chlorides to combat winter slipperiness on roads.
Keywords: liquid chloride, formation water, brine, corrosion rate, cement concrete pavement, winter slipperiness
The paper considers a method for obtaining gypsum foam based on various compositions of dry mixtures, including a foaming agent, various sorbents, and gypsum binder. Expanded vermiculite, perlite sand, and crushed expanded clay gravel were used as sorbents. The most effective sorbent of the above is the crushing waste from the production of expanded clay gravel. As studies have shown, foam gypsum with a density of 250 kg/m3 and a strength of 0.9 MPa can be obtained.
Keywords: Dry mix, adsorption, gypsum foam, gypsum binders, sorbent, expanded clay sand, vermiculite, perlite, foaming agent
This study investigates the applicability of pultruded glass fiber–reinforced polymer composites for structural components in oilfield infrastructure, focusing on their performance under aggressive environmental conditions. The introduction highlights the challenges of corrosion and logistics in traditional steel-based oilfield structures, proposing polymer composites as a viable alternative due to their low weight and high resistance to environmental degradation. The research objectives included evaluating the composites’ resistance to chemical exposure, freeze–thaw cycles, and climatic aging. Experimental methods involved testing density, water absorption, tensile strength, and modulus of elasticity under simulated oilfield conditions, including immersion in 1 wt% NaOH and 10 wt% HCl, frost resistance tests in 5 wt% NaCl, and cyclic temperature–humidity exposure. Results showed that the composites maintained ≥90% tensile strength, ≥85% flexural modulus, and water absorption ≤0.5% after 240 hours of exposure, with no significant degradation observed. Statistical modeling identified serviceability thresholds for specific environmental parameters. The study concludes that pultruded polymer composites are feasible for oilfield infrastructure, offering comparable mechanical performance to steel with reduced operational costs.
Keywords: pultrusion, glass fiber composite, polymer composite, oilfield infrastructure, environmental degradation, mechanical property, chemical immersion, freeze–thaw cycling, climatic aging
The results of studies of the strength properties of polydisperse reinforced composites based on gypsum fiber cement binders are presented. The increase in compressive strength due to dispersed reinforcement reaches 16% at the age of 2 hours and 19% at the age of 28 days, with bending by 69% and 75%, respectively. The compressive strength level of at least 90% of the maximum strength value occurs with an l/d ratio in the range from 1100 to 1800. When bending, at least 90% of the maximum strength value occurs at any l/d ratio with a reinforcement coefficient of μ = 1.3%. When reinforced with basalt fiber in combination with polypropylene fiber, the compressive strength is 1.67 times. The increase in bending strength ranges from 2.17 times after 2 hours to 2.3 times after 28 days.
Keywords: gypsum cement binders, polydisperse reinforcement, composites, compressive and bending strength
Currently, bitumen-polymer roofing materials are used in the construction of various types of buildings and structures, which have sufficient strength characteristics, wear resistance, water resistance and are convenient for installation. The mechanical properties of bitumen-polymer materials are significantly affected by the operating temperature. Of scientific interest is the analysis of the possibility of restoring the integrity of bitumen-polymer roofing materials at elevated temperatures, damaged as a result of mechanical stress at subzero temperatures. The article presents the results of testing the flexibility of samples of roofing bitumen-polymer materials at subzero temperatures. The samples that were damaged during the test were subjected to subsequent heating in a temperature chamber in order to identify the possibility of restoring the integrity of the material and the temperature at which the restoration would occur. The analysis of the test results showed the possibility of restoring the integrity of the material and the direct dependence of the quality of restoration of integrity on the heating temperature of the material.
Keywords: restoration of integrity, bitumen-polymer materials, roofing materials, flexibility, influence of temperature
The effect of gamma radiation on concretes of nuclear facilities and their components has been studied less than the effect of neutron radiation. In this regard, the purpose of this work was to assess radiation changes in concrete structures of various nuclear facilities under the influence of gamma radiation. The work presents computational studies of radiation changes in volume and compressive strength under the influence of gamma radiation in concrete structures of various premises of nuclear facilities. The calculations were performed using methods developed for the analytical determination of radiation changes in concretes and their components under neutron irradiation and heating. The rationale for their use was considered earlier. The calculations were based on the methods previously developed by the author for predicting radiation changes in fillers and cement stone under the influence of gamma radiation. It was found that under the influence of gamma radiation, significant radiation changes, especially in strength, occur and will occur in concrete structures of the considered premises of various nuclear facilities in most cases. Gamma radiation causes a decrease in volume and a decrease in strength, but it is different for concrete in different rooms depending on the absorbed dose rate. Radiation changes increase with an increase in the dose rate and the duration of operation. The calculated radiation changes in concrete under the influence of gamma radiation should be taken into account in the design, operation and especially when extending the operation of nuclear power facilities. However, the change in strength can be partially compensated by additional hydration and especially by an increase in strength due to carbonization. However, this is not taken into account in the calculations, since it has not yet been sufficiently studied. In this regard, the obtained results show the possible maximum effect of gamma radiation. Upon receipt of specific data on the effect of carbonization, the presented results can be adjusted.
Keywords: concrete, nuclear power facilities, nuclear power plants, gamma radiation effects, radiation changes in concrete, volume change, radiation changes in strength
Numerical studies of the temperature and humidity properties of three types of enclosing exterior walls have been performed using gas-silicate autoclave hardening blocks as the base, and a comparative analysis of the results of the study with the results of research by other authors has been carried out. The design features affecting the condensation of moisture in multilayer walls are revealed. It has been found that multilayer walls have a number of disadvantages that affect their performance and durability, in particular, the presence of materials with different vapor permeability and moisture absorption, which leads to the accumulation of moisture inside the wall. The prospects of using single-layer structures and the importance of choosing the right material for the finishing layer are shown. An example of the use of a finishing material based on acrylic and marble chips is given, and the need for further research of this material is shown.
Keywords: gas silicate block, condensation zone, plaster facade, finishing material, acrylic, marble chips
The article discusses methods that increase the effectiveness of additives for the preparation of concrete mixtures. The hydration of cement systems with various mineral and material compositions has been studied. The results of experimental studies confirming an increase in the effectiveness of plasticizing additives in optimizing the composition of concrete mixtures through the use of finely ground complex additives and the preliminary creation of hydrate neoplasms in concrete mixtures are described.
Keywords: concrete, hydration, concrete mix, additive, cement stone, mobility, efficiency, properties, strength
Toughening of requirements to buildings’ power efficiency enables development and implementation of modern lightweight concretes on efficient porous aggregates into building industry. The key demands to both lightweight heat-insulating and to fine concretes are ensuring low density index and thus low thermal conduction with high durability provided. There has been developed a lightweight heat-insulating fine concrete mix with the use of three fractions of granulated foam glass. To conduct the research there has been used a central composite design, which helped determine optimal consumption of separate fractions of granulated foam glass, and acquire a lightweight heat-insulating fine concrete with the lowest density. On the basis of obtained research results there has been carried out a calculation of thermal conduction ratio with the use of empirical formulae. The research results have been analyzed, and their descriptive statistics have been presented as diagrams and graphs. On the basis of the analysis of the research results there have been obtained regression equations and established influence degree of separate fractions of granulated foam glass on the density and thermal conduction ratio. There has been carried out an optimization of the material mix and the correlation between fine aggregate fractions calculated to provide the lowest average density.
Keywords: fine concrete, granulated foam-glass, thermal conduction ratio, average density, durability, experiment design, regression, mix optimization